STMicroelectronics LD57100J330R

Overview

LD57100J330R from STMicroelectronics is a fixed-output 3.3 V, 1 A ultra-low-dropout linear regulator (LDO) with NMOS pass transistor and dedicated VBIAS pin for operation down to VIN = VOUT. It delivers ±1% output accuracy over −40 °C to +85 °C, 40 mV typical dropout at 1 A, and 35 µA ground current at no load. Designed for post-regulation in space-constrained mobile power rails.

For engineers reviewing the LD57100J330R datasheet, LD57100J330R pinout, LD57100J330R application, or LD57100J330R equivalent, key selection criteria include bias-supply flexibility (VBIAS ≥ VOUT + 1.6 V or 3.0 V), active output discharge, thermal shutdown at 160 °C, and Flip Chip6 package compatibility with high-density PCB layouts.

Technical Context

The LD57100J330R uses an NMOS pass element driven by a separate VBIAS rail, enabling ultra-low dropout even when VIN approaches VOUT - unlike PMOS-based LDOs constrained by threshold voltage. Its internal reference (0.5 V) and error amplifier maintain tight regulation under dynamic load steps up to 1 A.

It integrates logic-controlled shutdown (EN pin), thermal foldback protection, and an internal discharge MOSFET (RON = 150 Ω) activated during disable. Supply rejection exceeds 75 dB (VIN) and 85 dB (VBIAS) at 1 kHz, with output noise of 27 µVRMS (10 Hz–100 kHz) for noise-sensitive analog/RF subsystems.

Key Specifications

Pinout & Package

LD57100J330R is housed in a Flip Chip6 package (0.8 mm × 1.2 mm, 0.4 mm pitch), optimized for minimal PCB footprint and thermal performance on thin PCBs. The die is mounted face-down with solder bumps directly contacting the board, eliminating wire bonds and reducing inductance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO applications.

Compared with XC6210B332MR-G and RT9080AL-33PU5, LD57100J330R uniquely combines sub-50 mV dropout, bias-rail independence, and active discharge - making it optimal for battery-fed systems requiring both efficiency and precise power sequencing.

Availability

LD57100J330R is available at Aetrix Electronics and suitable for smartphone power management, camera module regulation, wearable health sensor supplies, and industrial IoT edge node designs requiring stable component supply and long-term manufacturability.

Supply support for LD57100J330R includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog components for automotive, industrial, and consumer markets.

The LD57100 series belongs to ST's high-accuracy, ultra-low-dropout LDO portfolio, engineered specifically for post-regulation in battery-powered mobile and portable electronics where space, efficiency, and precision are critical.

FAQ

What is the minimum required VBIAS voltage for LD57100J330R?

The VBIAS pin requires either 3.0 V minimum or VOUT + 1.6 V (whichever is greater). For the 3.3 V fixed version, this means VBIAS must be ≥4.9 V. This bias rail powers the internal gate driver and error amplifier independently of VIN, enabling stable regulation even when VIN drops close to VOUT.

Can LD57100J330R operate with VIN lower than VOUT?

No - LD57100J330R is a step-down LDO and cannot regulate if VIN falls below VOUT. However, its ultra-low 40 mV dropout allows operation with VIN as low as 3.34 V (for 3.3 V output), making it viable for deeply discharged Li-ion cells or tightly regulated pre-regulator outputs.

Is the SNS pin mandatory in the fixed-output version?

Yes - the SNS pin must be connected directly to the VOUT net via a dedicated PCB trace (not shared with load return), as specified in ST's layout guidelines. This Kelvin-sensing configuration rejects voltage drop across PCB traces and improves load regulation accuracy to ±1% under full 1 A load.

Does LD57100J330R require an external discharge resistor?

No - LD57100J330R integrates an active discharge MOSFET (RON = 150 Ω) between VOUT and GND, activated automatically when EN is pulled low. This eliminates the need for external bleed resistors, saves board space, and ensures predictable, rapid discharge independent of load capacitance.